Figure 2 Design of the guide template based on 3D reconstruction. (A, B) Guide template design: Digital design of the pin guide template based on the 3D reconstruction of the humeral portion. The template was created using 3-matic 12.0 (Materialise, Belgium), ensuring it fit accurately onto the lateral condyle of the humerus. The final design of the guide template is shown, demonstrating its intended placement for pin insertion along the flexion-extension axis of the elbow joint. (C) The physical model of the distal humerus and the pin guide template were rapidly prototyped using polymer photosensitive resin via a 3D printer (Dreamer, Flsaforge, Zhejiang, China). The guide template is placed on the lateral condyle of the humerus to demonstrate its fit. (D) Inserting the guide pin through the well-designed channel to confirm whether the position is satisfactory.